The world’s population has never been bigger, and it’s still growing. but there’s a movement of “pronatalists” who see the slowing birth rate in wealthy, educated populations as a doomsday scenario in the making—and they’ve found their spokesman in one Elon Musk. Guest: Sophie Alexander, reporter for Bloomberg Want more What Next TBD? Subscribe to Slate Plus to access ad-free listening to the whole What Next family and all your favorite Slate podcasts. Subscribe today on Apple Podcasts by clicking “Try Free” at the top of our show page. Sign up now at slate.com/whatnextplus to get access wherever you listen. Public.com+Public Investing: All investing involves risk. Brokerage services for US listed securities, options and bonds in a self-directed brokerage account are offered by Public Investing, member FINRA & SIPC. Not investment advice. Public Investing offers a High-Yield Cash Account where funds from this account are automatically deposited into partner banks where they earn interest and are eligible for FDIC insurance; Public Investing is not a bank.Cryptocurrency trading services are offered by Bakkt Crypto Solutions, LLC (NMLS ID 1828849), which is licensed to engage in virtual currency business activity by the NYSDFS. Cryptocurrency is highly speculative, involves a high degree of risk, and has the potential for loss of the entire amount of an investment. Cryptocurrency holdings are not protected by the FDIC or SIPC. . See public.com/#disclosures-main for more information. Learn more about your ad choices. Visit megaphone.fm/adchoices